This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-079197, filed Mar. 19, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to the field of disk drives, and more particularly to a disk drive in which the parking ramp is prevented from contacting a surface of a disk even when the disk drive receives vibration or shocks.
2. Description of the Related Art
In disk drives, a representative example of which is a hard disk drive, a head (more precisely, a slider having a magnetic head element mounted on it) reads data from and writes data on a surface of a disk, i.e., a data-recording medium. Each head is mounted on an actuator comprising a voice coil motor (VCM) that is a main component. The actuator moves the head to a target position over the surface of the disk, under the control of a micro-controller (CPU). More specifically, the actuator moves the head to a position at which the head should read or write data from and on the data-recording area of the disk. The disk is rotated by a spindle motor.
A type of a disk drive is known, which comprises a loading/unloading mechanism (also known as xe2x80x9cramp loading mechanismxe2x80x9d). The loading/unloading mechanism is configured to park the head outside the disk during any non-operation period. During the non-operation period, the head neither reads nor writes data from or on the disk. The non-operating period includes a period during which the disk drive is activated, a period during which the power switch of the disk drive remains off, and a period during which data is transferred from the disk drive to the host system.
As FIG. 5A shows, the loading/unloading mechanism has a parking ramp 20 that is a member for parking the head 2. Parking ramps of various structures are available. Nonetheless, every parking ramp is designed to hold the head 2 unloaded from the surface of the disk 1 and to load the head 2 above the surface of the disk 1. More specifically, the parking ramp 20 has inclined surfaces 20A and horizontal surfaces 20B as is illustrated in FIG. 5B. Either inclined surface 20B may support an actuator. The horizontal surfaces 20B oppose each other, with an outer peripheral part of the disk 1 lying between them.
As FIG. 5A shows, too, the actuator has a suspension 3 that holds the head 2. The distal end of the suspension 3 functions as a parking tab 30. To achieve the unloading of the head 2, the actuator moves from any position over the disk 1 toward the outer periphery of the disk 1, until it reaches the marking ramp 20. The parking tab 30 then rides onto the inclined surface 20A of the parking ramp 20 and is lifted upwards. The head 2 held by the suspension is therefore parked at a prescribed distance from the surface of the disk 1.
As illustrated in FIG. 4B, the disk 1 has, on one surface, a data-recording area 10A, a loading/unloading area 10B and an outermost area 10C. The data-recording area 10A is a circular region, extending for some distance in the radial direction, from the center of the disk 1 toward the outer periphery thereof. The loading/unloading area 10B is an annular region that surrounds the data-recording area 10A. The outermost area 10C is an annular region, too, which surrounds the loading/unloading area 10B and usually remains unused.
In the loading/unloading area 10B, the actuator parks the head 2 on the parking ramp 20, accomplishing the unloading of the head 2. The actuator moves the head 2 from the parking ramp 20 to the loading/unloading area 10B to achieve the loading of the head 2. Namely, the actuator moves the head 2 between the data-recording area 10A and the loading/unloading area 10B.
The loading/unloading mechanism can maintain keep the head 2 out of contact with the disk 1 during the non-operating period that includes the period of activating the disk drive. This helps to improve the surface condition (surface smoothness) of the disk 1, successfully decreasing the flying height of the head 2. In other words, the distance between the disk 1 and the head 2 can be reduced to position the magnetic head element at a short distance from the surface of the disk 1. As a result, it is possible to enhance the read/write characteristic of the head 2. Hence, the density at which the head 2 record data on the disk 1 increases.
When the disk drive receives external vibration or mechanical shocks, it vibrates, inevitably undergoing deflection. Consequently, a part of the disk 1 (particularly, the outer peripheral part) may contact or hit a part (particularly, the distal part) of the upper horizontal surface 20B of the parking ramp 20, as can be understood from FIG. 4A. If the parking ramp 20 frequently contacts the loading/unloading area 10B of the disk 1, the following problem will arise.
As the parking ramp 20 repeatedly contacts the loading/unloading area 10B, the surface of the disk 1 is damaged and scratched, generating dust or forming projections on the disk 1 in some cases. The head 2, which remains at a low flying height above the loading/unloading area 10B, is very likely to contact the dust or the projections. If the head 2 contacts the dust or the projections, it will be damaged.
It is therefore necessary to prevent, as much as possible, the parking ramp 20 from contacting the loading/unloading area 10B of the disk 1 even if the disk drive receives external vibration or shocks. The parking ramp 20 scarcely contacts the data-recording area 10A. This is because the data-recording area 10A, which is the most important surface area of the disk 1, lies outside the region in which the parking ramp 20 is located.
A disk drive that comprises a stopper or an arm has been proposed, as is disclosed in U.S. Pat. Nos. 5,453,889 and 6,091,569. The stopper or the arm controls the deflection of the disk or protects the data-recording area of the disk when the disk drive receives external vibration or shocks. However, neither the stopper nor the arm can prevent the parking ramp 20 from contacting or hitting the loading/unloading area 10B of the disk 1 when the disk drive receives external vibration or shocks.
An object of the present invention is to provide a disk drive comprising a parking ramp, in which the parking ramp is prevented from contacting a disk, particularly the loading/unloading area thereof even if the disk drive receives external vibration or shocks.
In accordance with one aspect of the present invention, there is provided a disk drive including a parking ramp that is configured to avoid contact with the loading/unloading area provided on the surface of a disk.
The disk drive comprises: a spindle motor; a disk which has a data-recording area, a loading/unloading area and an outermost area and which is rotated by the spindle motor; an actuator which holds a head for reading and writing data on and from the disk, which moves the head over the disk and which performs loading/unloading of the head; and a parking ramp member which is arranged near the outermost area of the disk, which has a parking part and a surface. The parking part of the ramp member is configured to hold a part of the actuator while the head is being unloaded from the data-recording area. The surface of the ramp member faces the loading/unloading area and outermost area of the disk and is spaced therefrom by a prescribed distance. The surface of the parking ramp member is spaced from the loading/unloading area of the disk by a first distance and from the outermost area of the disk by a second distance that is shorter than the first distance.